To achieve this, it is known from the state of the art, particularly from document EP 2138861 (hereafter, D1), to locate objects in the environment.
To achieve this, D1 provides a system for locating a set of objects, comprising:
a tool configured to cooperate with each object of the set in a so-called cooperation position, the tool being equipped with a transmitter of an Ultra Wide Band signal (UWB),
a plurality of receivers of the signal arranged to receive the signal.
The transmitter and the plurality of receivers form ranging means enabling to locate the tool in a cooperation position, and thereby to locate the corresponding object.
“Ultra Wide Band” means a signal having:
an absolute bandwidth measured at −10 dB greater than 250 MHz, or even greater than 500 MHz if the United States definition of UWB is considered, or
a relative bandwidth measured at −10 dB greater than 20% of the central frequency.
UWB-type signals are particularly suited to an industrial environment since such signals are little confronted to multipath issues.
The location system of D1 is not totally satisfactory since it requires a minimum number of receivers to use the ranging technique, called time difference of arrival, TDOA technique, see § 0042. This minimum number of receivers is 3, due to a triangulation calculation. Further, the accuracy of the location system of D1 may be strongly decreased by measurement biases introduced by the environment, see § 0045. This may result in an insufficient accuracy for certain applications.